The games concept obviously had the Wii in mind so I am unsurprised it is being released there first. Wii's are cheap (Relative to a new 360, PS3 or PC) if you are a huge Disney fan I can see them buying it just to play this game. Something I don't think was lost on Nintendo with making it an exclusive. (For now- not sure if this is an exclusive forever situation)
I did not play it at PAX but I did see it being played. I can back Susan up on how nice this game looks. It might be the best looking game ever on the Wii. It is amazing what they got out of that little system. The game play looked solid to. I know we are getting it as my Wife is a huge Disney fan but it is nice to see we will be getting a game I will have fun playing to.